1. Field of the Invention
The present invention relates to apparatus for recording a video signal and, more particularly, to a recording apparatus that can be selectively set into a normal mode or a high band mode.
2. Description of the Prior Art
In a rotary head type videotape recorder (VTR) in which the luminance signal is frequency modulated and the chroma signal is converted into a low band frequency and recorded, the horizontal resolution and thus the picture quality can be improved by raising the carrier frequency when the luminance signal is frequency modulated and by widening the frequency deviation. Therefore, in such a VTR, it is good practice to provide a recording mode in which, when the luminance signal is frequency modulated, the carrier frequency is set to be higher than the frequency that has conventionally been used, thereby improving the picture quality.
Hitherto, in the recording format of, for example, an 8-mm VTR, the carrier frequency when the luminance signal is frequency modulated has been set to 4.2 MHz at the sync tip level and 5.4 MHz (or higher by 1.2 MHz) at the white peak level. In such an 8-mm VTR, in order to realize high picture quality, it is common practice to set the carrier frequency when the luminance signal is frequency modulated to 5.7 MHz at the sync tip level and 7.7 MHz (or higher by 2.0 MHz) at the white peak level. Such a recording mode is hereinafter called a high band mode. The conventional recording mode is hereinafter called a normal mode.
In order to improve the picture quality still further the carrier frequency when the luminance signal is frequency modulated is sometimes set to 7.0 MHz at the sync tip level and 9.0 MHz at the white peak level. Such a recording mode is hereinafter called a super high band mode.
In a VTR that can record in the high band mode or the super high band mode in addition to the normal mode, it is necessary to control various components of the VTR in accordance with the recording mode. That is, it is necessary to switch the characteristics of the FM demodulator, the pre-emphasis characteristics, the characteristics of the recording amplifier, and the like in accordance with the recording mode.
One constraint imposed is that recording in the high band mode or the super high band mode cannot be carried out using "ordinary" or "normal" tape. In the case of recording in the high band mode or the super high band mode, it is necessary to use a tape that will accept a high density recording. Such a tape can of course also be used for recording in the normal mode, in which the recording is of a lower density.
As mentioned above, in a VTR capable of operating in either the normal mode or the high band mode, it is necessary to switch various setting states in accordance with the recording mode selected.
It is very troublesome to execute such a setting operation manually. Moreover, when such a setting operation is manually performed, mistakes are often made. For instance, in spite of the fact that a normal tape has been loaded, the high band mode may be set. In such a case, normal mode recording is not executed. Moreover, high band mode recording is not properly executed, since the tape is not capable of accepting a recording of the requisite density. Alternatively, in spite of the fact that a tape for the high band has been loaded, the normal recording mode may be set. In such a case, the recording will be carried out, but without achieving the picture quality of which the loaded tape is capable.